Just another piece of information, if you have a Smart Phone or similar phone, people can also track you this way. I saw a video of this, for example, they picked someone out at random on the street and asked if they had a Smart Phone, if they said yes, they used the persons phone, and knew where exactly that person had been, and at what time. To me, that's scary, and one of the many reasons I don't have a "hi tech" phone, or a blog, I also don't get on facebook or sites like it.